List Slack channels

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful behavioral context beyond that: membership-gated visibility and the chat:write.public exception for posting. It doesn't describe pagination or return shape, but with annotations present a 4 fits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, no waste, with the core scope front-loaded before the visibility caveats.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, but the description covers the key semantic an agent needs: which channels appear and what membership means. It could say more about returned fields or pagination, but it is adequate for a filtered list tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema documents limit, query, types, and member_only. The description adds meaning around membership gating but references 'is_member', which is not a parameter name (the parameter is member_only) – this could confuse an agent mapping it to input. Baseline 3 for full schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Uses a specific verb (List) and resource (channels) with an explicit scope: 'channels the bot can see'. The optional name filter is stated. It doesn't explicitly differentiate itself from siblings like conversations_history, but the resource is distinct enough to route correctly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear context on visibility: private channels and DMs appear only if the bot is a member, and explains the is_member=false implication. It stops short of naming alternatives or stating exclusions ('use X instead'), which keeps it from a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.